Conventional video providing services provide videos by using media such as radio waves which cause less errors at the time of transmission as in broadcasts and provide videos by using media such as tapes. For this reason, objective assessment techniques of deriving objective assessment values of video quality with accuracy equivalent to subjective assessment by comparing a reference video with a deteriorated video have been studied to derive proper assessment values mainly with respect to coding distortion.
As a conventional objective assessment technique, therefore, there has been proposed a technique of estimating subjective quality with accuracy equivalent to subjective assessment by deriving the average deterioration of an overall frame or an average deterioration in the time direction by using “a correction coefficient for each video”, “SN”, or “a deterioration amount based on a Sobel filter” on the basis of the fact that deterioration due to coding distortion is relatively uniform spatially and temporally (see, for example, Japanese Patent Laid-Open No. 2004-80177 and U.S. Pat. Nos. 5,446,492 and 6,704,451).
In addition, according to the techniques disclosed in Jun Okamoto, Noriko Yoshimura, and Akira Takahashi, “A Study on Application of Objective Video Quality Measurement”, PROCEEDINGS OF THE 2002 COMMUNICATIONS SOCIETY CONFERENCE OF IEICE and Jun Okamoto and Takaaki Kurita, “A Study on Objective Video Quality Measurement Method Considering Characteristics of Reference Video”, IEICE Technical Report, Vol. 103, No. 289, CQ2003-52, September, 2003, pp. 61-66, a subjective assessment value can be estimated with target accuracy.